Of course, you exist in every possible world which would produce that mindstate, but some are 'vaster' than others, leading you down the most probable courses.
This is basically the answer. You can think of different worlds as having different amounts of "magical reality fluid," or "measure." You are more likely to be in one of the worlds with lots of magical reality fluid - if there are two worlds with a 2 to 1 ratio of magical reality fluid, and you otherwise have no information distinguishing them, your probabilities about which world you're in should likewise have a ratio of 2 to 1.
Suppose that going to sleep or losing grasp of your surroundings opens a wider space of worlds you could exist in, which jumps you into another reality along with consistent memories of it.
There are no jumps. There is nothing to do any jumping - no soul, no thread of consciousness above and beyond your physical state (at least not when it comes to assigning probabilities - when it comes to utilities, you are allowed to value continuity of experience or content of your memories if you want). In any given world, you either exist or you don't. If you go to sleep in this world, the only way to leave is to die in your sleep.
The idea of sleeping being simpler than waking, and therefore there being more sleeping boltzmann brains of you than waking ones, is interesting, and debatable, but basically irrelevant. You go to sleep, you wake up. The boltzmann brains evaporate back into their constituent atoms. Life goes on.
Yes, but don't I have to have one set of experiences? Even asleep, more stable universes still have a much greater measure than the Boltzmann brains, but the universes that had a dominant measure when I was awake no longer do so. So I could easily awake into a different world, with perfectly consistent memories when I reach for them. That's what I mean by 'jumping.'
(Also, I wasn't really talking about Boltzmann brains. I'm just saying that if Dust Theory were true your lack of consciousness should give more chaotic, dreamlike universes a larger measure. Your mind would slowly dissolve.)
Dust theory implies that everything outside of my perception is in flux. Your experiences have to find themselves in a world in which they could have conceivably formed. Of course, you exist in every possible world which would produce that mindstate, but some are 'vaster' than others, leading you down the most probable courses.
Suppose that going to sleep or losing grasp of your surroundings opens a wider space of worlds you could exist in, which jumps you into another reality along with consistent memories of it. I can't figure out if this would be the case, or if my consciousness would most likely just dissolve, with only those beating trillion-to-one odds waking up in the morning. Or maybe my pool of 'experience' stays active when I sleep, even if I'm not aware of it. Either way (though I think Dust Theory is probably false) I'm afraid to go to sleep anymore.
I also do not understand the argument being made here: http://lesswrong.com/lw/1jm/getting_over_dust_theory/. Can someone explain to me please?
I posted these questions on other threads but I didn't get many answers. Sorry.
EDIT: Look, the first question boils down to: does my unconscious mind affect my measure? If so, than it isn't much different from being awake. If not, then all my problems seem to apply.
It occurs to me that not only would signing up for cryonics and then killing yourself before you could sleep is rational under these circumstances, but that the death of the universe can be escaped by simply rearranging your mind to believe it is in a universe where eternal life is possible, then ceasing its activity.